To characterize the clinical pharmacology of a given agent we take the following step-wise approach: development of an analytical method for quantitation in biological fluids; characterization of pharmacokinetics; pharmacokinetic modeling to govern future dosing schedules; evaluation of plasma protein binding; determination of renal elimination; in vitro metabolism studies to characterize the enzymes involved, metabolites formed and possible drug-drug interactions; development of pharmacodynamic correlations with efficacy and/or toxicity; pharmacogenetic approaches to further understand factors responsible for interindividual differences. Our research efforts have focused primarily on agents that target the aberrant biology of neoplasms (agents that target signal transduction pathways, angiogenesis inhibitors, cell cycle inhibitors, protein kinase inhibitors, antagonists of peptide growth factors) and on novel ways of administering cytotoxic agents.